Data Storage Devices/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim and Moby are at the Museum of the Computers. They are looking at an early computer. MOBY: Beep? TIM: They're magnetic tapes. They used to store data on those. Tim reads from a typed letter. TIM: Dear Tim and Moby, what's the best way to store my homework? CD? DVD? Flash drive? Help! From, Michael. Well, depends on what you're looking for. CDs and DVDs are the cheapest solutions, but those little USB flash drives are really convenient; you can carry them around in your pocket. An image shows a CD, a DVD, and a USB drive. MOBY: Beep. TIM: Actually, they're not so different from each other. They're all designed to store data, which is any kind of information: homework, music, photos, movies, anything! Images illustrate the stored information Tim lists. TIM: And they're digital, which means they store data in a number language called binary. Instead of words, binary uses a combination of ones and zeros. Several rows of ones and zeros appear. TIM: Each one and zero is called a bit, and eight bits together are called a byte. A combination of eight ones and zeros, or bits, are highlighted to show a byte. TIM: Using binary code, computers can store any information we can give them. MOBY: Beep. An animation shows a screen above a keyboard. A finger types the letter A, which appears on screen with the eight-character byte below it. TIM: The average CD can hold about seven hundred and fifty million bytes of data. An image shows a CD. TIM: That's close to a thousand novels. Using compression software, you could squeeze ten times as much on there. An image shows stacks of novels. TIM: But that's nothing compared to DVDs, they can store almost five billion bytes of information. Side-by-side images show one DVD and several CDs. TIM: And many flash drives can even hold even more than that. An image shows a flash drive, and then the drive with rows of CDs behind it. MOBY: Beep. TIM: Well, CDs and DVDs are optical media devices. That means they store data visually, sort of like a book. An image shows a page from Charles Dickens's novel "A Tale of Two Cities." TIM: Only instead of words, they encode their information in the form of bumps. These bumps are placed in a spiral from the center of the disc to the edge. An image shows a disc. A detail of the disc shows the bumps. TIM: When you load a CD or DVD into a computer, it gets spun around thousands of times per minute. The laser inside the drives reads the bumps and flat areas as ones and zeros. As the disc spins, rows of ones and zeros appear behind it. TIM: DVDs use much smaller bumps than CDs, so they can store more data. All the bits on CDs and DVDs are numbered. MOBY: Beep? TIM: Yeah that's true. The main storage device, or hard drive, in your computer spins around, too. And so do portable floppy disks. But those store information magnetically, instead of optically. MOBY: Beep. Side-by-side images show a hard drive and a floppy disk. TIM: Floppy disks have become less popular because they don't store nearly as much data as CDs and DVDs. MOBY: Beep. Moby holds up a flash drive. TIM: USB flash drives, or thumb drives, are different from all of these other media because they're solid state devices. An image shows a flash drive. TIM: That means flash drives have no moving parts. An animation shows the other drives with their discs rotating: hard drive, DVD and CD, and floppy drives. TIM: You just plug one into a USB port, and your computer treats it like another hard drive. Side-by-side animations show a flash drive being plugged into a USB port and the flash drive appearing as the "E" drive on the computer's file manager. TIM: Like any computer chip, flash drives store data on tiny transistors. A transistor is basically an electric switch. It's either on or off. An image shows a transistor. TIM: The position of the switch corresponds to a binary zero or one. With millions or billions of transistors on one chip, that adds up to a lot of information. Flash drives use a special kind of chip that doesn't need a constant supply of electricity to hold data. An image shows a flash drive chip. TIM: Besides being able to hold more information in less space, thumb drives have a few other advantages over CDs and DVDs. Zero moving parts means they're less likely to break, and they're completely silent. And because optical media devices need to have a laser physically move to access data, thumb drives can retrieve information a lot faster. An animation shows a laser moving over a spinning disc to access data. TIM: On the other hand, USB flash drives are still a lot more expensive than CDs and DVDs. MOBY: Beep? TIM: Right, the memory cards inside digital cameras, PDAs, and other handheld devices are a lot like USB flash drives. They don't connect with a simple USB interface, but their solid state chips work on the same principle. An animation shows a memory card sliding out of a digital camera. Moby takes a USB drive out of his ear and plugs it into a computer. Moby's face appears in a grid on his computer monitor. The computer image of Moby beeps. MOBY: Beep. Beep. Moby's computer image responds and they exchange beeps. Tim observes. TIM: Okay, that's weird. Category:BrainPOP Transcripts